Keoman

iTrader: (3)

I did mine myself, not hard at all. After you remove them, buy the tool and tap the holes (they are already the right size for the tap) and then go have them machined flat and get some good screw in studs (not the cheap speedway studs i got) and you'll be golden.

https://www.texas-speed.com/p-439-pa...ve-spring.aspx
http://www.alexsparts.com/beehive-va...-applications/
I can personally guarantee that these springs and retainers will fit vortec heads. I measured my max lift with a dial indicator and got .560" for my lowest value and I DIDNOT have my retainers machined for extra clearance. They suggest .030-.035" more with MODIFIED retainers which would have put me around .590". Most people recommend a "cush" distance of around .060" so you would be able to safely run a rocker/cam combo that put you around .530" lift with no worries at all.
Stock vortec installed height is about 1.700" so you pick up a little bit of closed seat pressure which you benefit from in the long run.

gbettner

iTrader: (2)

Stealth ram alternative fuel rail parts all ordered ( used post#247 from the 'STEALTH RAM ALTERNATIVE FUEL RAIL" thread) and fuel pressure regulator/ memcal sent to Tuned performance for mods/programming. Next on the list is settling up with the machine shop and buying a crank kit to assemble shortblock. I decided to wait on the roller rockers till later in the build since they are so expensive and one of the last things I'll need.

Thinking about purchasing a piston ring filing tool but undecided.


Waiting on a big plow check and another snow storm is hitting this afternoon. Woohoo! More parts on the way very soon!

gbettner

iTrader: (2)

While waiting on some more funds I'm trying to research and plan a couple more things.......

Static compression ratio,
I have stock deck height, flat top .030 over pistons with 4 valve reliefs, stock vortec 062 heads (resurfaced). Stock rods, stock crank, stock deck height. Not sure what the best choice on head gasket is for compression ratio. Will be running the Lunati Voodoo 20080721 cam with 1.6 rockers.

Just wanting to buy the right head gaskets as they really matter.

I found alot of threads talking about and started getting myself confused. Sorry to be lazy but my best bet is always asking your guys advice.

What should be my target static comp. ratio and obtained by what thickness gasket?

Then what would my dynamic be out of curiosity after static is decided on?

Thanks

jokerZ71

What is the part# on the Speed Pro pistons you are using.The 345's come in 3 different pin hgts. 1.560",which is the stock hgt,1.540",& 1.548".If your block is undecked & you use the shorter pistons,they will be way too far down in the cylinder.You need to know your actual deck hgt as installed to accurately determine SCR & DCR.You wanna aim for .035 to .045 quench/squish distance.(total distance between piston top & head w/ gasket installed.This will produce the best power,most efficient burn,& help deter detonation.

gbettner

iTrader: (2)

Thanks for spoon feeding that. I'll have to check on piston part #. I'm sure it's stock but I'll confirm. The machine shop purchased them so they could do the bore job. I didn't have the block decked so I can't just say "stock deck height? (Just askin) Is that something I need the machine shop to measure?

InfernalVortex

iTrader: (4)

Deck height on the blueprints is 9.025 The height of the piston in the bore is supposed to 9.000 if I recall... But that number is determined by build tolerances in the block's mains, crank casting and machining variances rod bearing variances, rod length variances, and piston machining variances. What it's supposed to be on paper may not be what it actually is. Even the block itself will have varying deck heights from bore to bore.

BUT, assuming stock deck height and that the factory machining is accurate (they are machined to be "good enough", that's about it, dont expect much) and the specs on all your parts are accurate, and you get 1.540 pistons, you're pistons are going to .045 in the hole before the headgasket. If you do that plus get a normal .040ish head gasket, your pistons are suddenly .085 inches below the quench surface of your cylinder head. This will ruin the compression, detonation resistance, fuel mileage, and power production of your engine. In my opinion it's bad enough that if the tolerance stack leaves your pistons .085 in the hole, it's worth it to spend the money to get new pistons. You're not going to find a -.005 head gasket to balance that out and most of your investment in building the engine and buying parts is going to be wasted. You dont want to have to do this twice.

Im running a set of H345NCP (C for coated skirts) speed pros, and they (allegedly) have a 1.560 pin height. My quench is around .065, and that's not good. I have plans to go to a thinner gasket... .085 is just awful.

Also, that cam should work REALLY nice with those heads. AIm for around 9.5:1. If you get the quench in the right range, you should be getting pretty close to 10.0:1, but with Vortecs that should be just fine. You dont need as much timing advance with these as you do with some other heads. My max advance is 32 degrees and I've heard of other guys not seeing gains past there either. It depends on a lot of things but that's the general idea. You SHOULD be somewhere around 340-370hp with that cam... maybe more. But that's only if you get the quench right. If you dont get the quench in the right range you're going to leave a lot of power on the table.

Also, one last thing... Vortecs dont see any flow increases past around .480-.500 lift. The ports actually "Stall" around that lift point. 1.6 rockers will not help you much at all. The lift of that cam with normal rockers is high enough you need to be very, very careful about guide to retainer clearance but if you have the retainers milled down you should be okay. But the complications with 1.6 rockers plus the lack of gains you're going to get from them... you may want to go back down to 1.5s and keep your valvetrain geometry more managable. With some heads and cams they're a big help when you're trying to get more power with less duration, but you're right in the middle of the vortec sweet spot in duration and already way past the point of diminishing returns when it comes to valve lift. Depending on what you read, some say the flow numbers actually decreases as lift goes past .500 due to the weird nature of the vortec ports.

Just some food for thought.

https://www.thirdgen.org/forums/tpi/...w-numbers.html

http://image.carcraft.com/f/42379923...+Flow+Data.pdf

jokerZ71

If they used a shorter pin hgt piston referred to as a "rebuilders piston",it will be farther down in the cylinder which will change deck hgt.Stock deck hgt on a SBC is .025" with a stock piston with a 1.560" pin hgt.If they use a piston with a 1.540 pin hgt,your piston will be .045 in the hole vs .025.There will be no way to have a tight quench w/o decking the block or using a taller piston.Even if you used a .015 shim headgasket,you're quench would .060 which would be of no benefit @ all.If you can list the piston#,actual deck hgt,cam specs,I can run the #'s & tell you what your final SCR is & what you DCR will be.

gbettner

iTrader: (2)

Thanks for the great info! If you happened to read towards the beginning of this thread I've had some issues with the machine shop that currently has my block, I've found another shop to machine down my rocker stud bosses to complete my heads so after a little reading it looks like I'll probably be taking them my block too for a zero deck hgt job as soon as I find out piston part # for sure.

So just to be clear, in your example above, your saying in order to have a good .040 quench with a stock deck hgt (.025) and a stock piston with a pin hgt of 1.560 I would need a thin metal .015 head gasket?

I'm just trying to get this locked in my head.

If I find out they did in fact get the "rebuilders" piston with 1.540 pin hgt. then my best plan is zero deck block and .040 head gasket?

Sure seems real obvious but please confirm or deny.

THANKS!

gbettner

iTrader: (2)

Holy smokes I missed this post to begin with. You just took me to school! Amazing information! I love this forum. As soon as I find out what pistons they set me up with I'll decide how to proceed. I don't mind getting another set of pistons ( or zero decking the block) now I understand the pin hgt.I'll see what the machine shop stuck me with Monday.

Thanks a million. I just learned a s--t ton!

InfernalVortex

iTrader: (4)

Just so you have a better idea of where the numbers are pulled from...

This is a typical 350:

3.480" stroke
5.7" rod
1.560" piston compression height.

stroke: 3.480/2 = 1.740"
This is because the stroke is the full travel, but the crank journal is centered half that distance away from the crank centerline. So at top dead center the big end of the rod is 1.740" away from the crank centerline pointing at the top of the bore.

1.740"+5.7"+1.560"= 9.000

The block is 9.025", and the factory used a steel shim head gasket to get it right around the .040 quench number we all aim for.

If you use, for example, 6 inch rods, you'd need a compression height piston of 1.260. Or if you use a 3.75 stroke crank, you need a different compression height, etc. Hopefully this gives the number a little context.

jokerZ71

That is correct.If they used a 1.560 piston,you can deck the block for 0 deck,or,use a shim gasket.Personally,I don't like shim gaskets.Your deck & head surface need to be in really good shape for a good seal.What I would do is have approx .010 taken off the deck & use a GM .028 composite,or,the MR Gasket .025.This would give you .043 or .040 which would be good.If they used the 1.540 piston,you would need to take .045 off the deck for 0 deck.That is too much to remove.
Find out for sure about your pistons & then we can come up with the best plan to get you where you wanna be.

gbettner

iTrader: (2)

OK, looks like I'm safe........ Part #H345DCT 1.560 comp hgt.. Tried to copy and paste specs...

350 BASED engine (4.000 bore x 3.480 Stroke) press pin, coated skirt. Pistons sold in sets of 8, price shown is each. Do not use in 4.3L V6!

Sealed Power® Digital Diamond Profiled™ Pistons are perfect for engine builders looking for ways to build a cleaner-burning, longer-lasting vintage Chevy SB engine. This advanced piston technology lets rebuilders equip this popular engine with the ultimate in modern piston materials and engineering – while still keeping that classic engine “classic.” Sealed Power

DDP Pistons feature:

DDP™ Technology: Digital actuated diamond turning process produces precision skirt profiles.
•Barrel profile: Creates an oil wedge between the skirt and cylinder wall.
•Thermal Arching Compensation™ (TAC) Ring Groove Geometry: Machined uptilt offsets thermal “arching” distortion; squares the ring face to the cylinder.
•Next generation DUROSHIELD® coating: Reduces friction and wear.
•Precision-machined pin bores: Accommodate fixed or floating wrist pin installation.
•Can be used as full floating assembly. You must purchase 16 of LR63 lock rings.
•Specify your size below.




Ring dimensions 5/64, 5/64, 3/16
Flat Top; 4 valve reliefs
Compression dist 1.560
Deck Clearance .025
Skirt Clearance .0010

TGSeavs

Quick question on the vortec roller block... Can you use all the existing front accessories or do you have to switch over to the truck setup? Also what are you going to use for headers?

Thanks,

Nick

gbettner

iTrader: (2)

Well I'm closing in on having everything I need.

Going to order my rockers today ( I think I will switch to 1.5's as suggested) and I think that just leaves me with waiting on Southbay injectors to call me back after they receive my injectors I shipped them for trade in, picking up heads from machine shop ( already paid for), FPR and custom tuned chip from Tuned Performance have been shipped and on the way from Doctor Brian, main /rod bearings arriving any day now , pushrods, gaskets, and a torque converter.

I was looking through Summit and found way too many options on a torque converter for me to decide on my own. Can you guys suggest a good stall speed (2000?-2500?)and the cheapest brand of stall converter I can get away with? I don't want to pay top dollar for the best of the best nor do I want the the crappiest cheep-o. Just want a good quality one that will work good keeping in mind I'll be driving it in town often.

Thanks for all the help from everyone so far!

-Gary

86LG4Bird

iTrader: (1)

It scares me when I see stuff like "Summit" and "cheapest brand" mentioned when somebody is shopping for a torque converter!
I've not looked at Summit's TC offerings for quite a while, but I'd be surprised if they have anything worth considering.
Ideally, you could find something like a used Yank or Vigilante. But if buying new, for the "cheapest brand of stall converter I can get away with", I'd recommend Edge. I've used several of their 9.5" Street Edge converters with good results. Andre is the guy to talk to. http://edgeracingconverters.com/
Edge tends to run loose compared to Vig, and especially compared to the Yank SS series, so I'd ask him to build a tight 9.5" for you, close to 2600 stall. I have an Edge 2800 in the Firebird right now; it feels about like a 3000 Vig and a SS3600 Yank. For the engine you're doing, I'd go no lower than 2600 for sure. And don't even waste your time and money on a 12" converter; the performance is just not there.
What year is your trans? They changed to 30 spline input shaft sometime in the 85-86 timeframe. The converter guy needs to know that.

gbettner

iTrader: (2)

I tried phrasing it properly, I just don't want to shell out more than necessary for a decent converter. I don't know anything about the brands but I do know I shouldn't buy the cheapest so I'm just after a decent quality moderately priced converter that will do a good job without forking over hundreds more for the best of the best.
Thanks for the info, I'll look into that and get a quote from Andre. And my transmission is a 700r4 out of an 85 Corvette. I can count the splines here in a couple hours. Thanks!

gbettner

iTrader: (2)

I JUST SCORED HUGE AT THE LOCAL PIC-A-PART! COMPLETE DISK BRAKE POSI REAREND WITH 3.73 RICHMOND GEARS OUT OF A 92 CAMARO.... 100 bucks!!!!!

Tuned Performance

iTrader: (92)

So are you sending me the cat back ? I need it lmao

gbettner

iTrader: (2)

OK a couple developments. Finally got started building the short block, thoroughly blew out the block with an air hose and scrubbed down really good with hot soapy water, plastigauged the crank tonight and got a perfect .002 oil clearance on 4 of the 5 mains.... #5 was closer to .003. so I should be good.

I never actually plastigauged rods before. It would be a real pain in the butt since it's the vortec rods requiring torque angle gauge but I hate to cut any corners.

STILL waiting on machine shop to get my heads done but not really in a hurry for them so no need to rush them.

Now for the unbelievable part........

My sweet wife is letting me build the engine in the house!

1gary

Gar-I get this image in my head you saying "honey help me move the dinning rm table over in the corner".Yep-she is a keeper.

skinny z

Once you have the short block assembled, despite all of the calculations, it's important to actually measure the piston relative to the deck. Then you'll have the ACTUAL value. On a stock crank/stock rods arrangements, don't be surprised to see variances by as much as .010" or more. Check all of the deck heights and go from there. First hand experience with an older 010 350 block (circa 1979 Chev truck) with OEM crank/re-sized rods and Speed Pro hypereutectic cast pistons showed piston below deck ranging from .025" to .036". Getting that perfect would require the crank and rods to be fully indexed. $$
As for the "zero" deck height target, keep in mind that if you go that route, you've limited yourself in any future rebuild should the block require decking again for any reason. I've never understood why the zero deck is so coveted when for example, a piston that's .014" down when combined with a .026" head gasket gives a very workable .040" piston to head clearance number.

gbettner

iTrader: (2)

Stalled out on build for the week, had to take on another side job to help pay for the torque converter I want to get. ( engine swap in an 05 Chevy classic outside in gravel driveway since my Camaro is hogging the garage ). I'll have it done Saturday hopefully and be ble to get back on shortblock Sunday.

Got my heads back finally and they look pretty good. The old grumpy guy even gave me his piston ring squaring tool he made his self when I asked for an old piston.

86LG4Bird

iTrader: (1)

What TC did you decide on?

gbettner

iTrader: (2)

I was going to go with the street edge you suggested but it's pretty pricey. There's one for like 350 that's "mild street" and one for about 550 that's "street". I think I read the "street" one is the 9.5" you were talking about but the wifey poo about pooped a kitten when I told her how much it was. Can't blame her, I've spent A LOT on this thing. Took on this extra side job to smooth thing over a smidge.

3rdgenmaro

iTrader: (9)

I learned my lesson on cheap converters the hard way. It is worth it to put a good one in the first time.

skinny z

I'm not sure what exactly defines a "cheap converter" however for my application the TCI 10" Street Fighter performs very well. At $550 it's hardly "cheap" dollar-wise but I know you can spend a lot more.

http://www.tciauto.com/tc/streetfigh...e-lock-uphtml/

For me, it provides enough stall to get into the revs when I'm on the street. The lock-up is essential and it performs as expected. The only thing about it that I'd like to change is to be able to foot brake to a higher rpm. As it now, once I'm up to 2000-2500, the car will start to creep. I tend to keep the revs right around 2000 when staged. Another 1500 rpm or so would be nice though. Peak torque for me is in around the 4000 rpm mark and leaving closer to that would undoubtedly imporve my 60' time. My personal best is 1.7 flat but I see cars with less or equal performance quicker in the 60.
As for durability, I've got thousands of miles and hundreds of launches on this unit and have no converter issues that I can relate.

3rdgenmaro

iTrader: (9)

Well mine was cheap based on it being labeled as a performance converter. $450 for a 10" converter was just slightly more expensive then some of the no-name ebay stuff. I know some people have used them with success, but of the two I had, both were defective. First one right out of the box, second one lasted just past the warranty period and the hub cracked.

I wanted my cake and wanted to eat it to, and it ended up costing me. Cheap converters work everyday for someone, but the failure rate is higher. And for me that failure rate bit me.

skinny z

For the average joe, I'd think that any name brand converter with a history and decent service record would get the job done the same as mine has (touch wood). Personally I would avoid the off brand stuff (as I do with everything).
Some of the posters here are deeper into racing than I am and have first hand accounts of the benefits of more expensive converters (as in more than my $550) like Yank or Vigilante.

gbettner

iTrader: (2)

Yeah, the $550 street edge 9.5" converter 86lg4bird suggested is the max for me.Can't go deeper than that. My wife would string me up.

gbettner

iTrader: (2)

Thanks for the link skinnyZ, I'll check that one out too!

skinny z

Now I'd like to know the real difference between the two. I see that mine and the one spec'd for you are the same price. I didn't see a mention of a lock-up clutch on the Edge website although at the Pro Built Automatics site they list the 9.5" Edge converter as a lock-up unit.
Based soley on what I've heard from racers, the Edge outperforms many. I've never heard anything about TCI one way or the other.

3rdgenmaro

iTrader: (9)

I haven't heard anyone complain about the TCI. I have heard that some people claimed that they weren't on par with the Edge, but I haven't heard any failures or disappointment from TCI.

86LG4Bird

iTrader: (1)

Whatever you do, please don't spend any serious money on a 12" converter.
I'd consider 12" and performance mutually exclusive when you're talking about a vehicle with anything but a stock cam in it. The GM S10/Vette (~2200 stall rating) converter is about as good as it gets as far as performance goes with 12" converters. Compared to the very tight converters (~1400 rpm stall) that came in some (possibly all?) auto 3rd gens, the S10 TC is a decent upgrade, and at one time could be purchased from GM for $150-$175. I haven't looked for one in the last 4-5 years.
I've seen, installed (against my better judgment), and driven guys' vehicles with 12" converters from B&M, TCI, and even Yank, and they were all varying degrees of disappointment performance wise. The S10 does just as much for half the cost. B&M and TCI 12" TC's do not have a stellar reputation for quality (reports of excessive heat generation in their higher stall ratings) but I haven't witnessed that, since I never had one in my own vehicles. No experience at all with the 10" TCI.

For performance converters, my ranking based ONLY on what I've used is:
Yank, Vig & Coan tied, then Edge. I run an ATI 8" in the Impala now, but it's a race converter, no lockup, not what I consider streetable, so I excluded that.
The Yank 9.5" SS series is unbeatable for performance, streetability, and quality, but it's one of the pricey ones. Edge is right up there in performance (9.5" Street Edge, NOT Mild Street Edge!), but lacks some top end efficiency, which will not be a factor at 3000 or lower stall rating, and is not a billet front cover so will not take repeated WOT lockup abuse like the Yank, Vig, & Coan will. But in a light vehicle like a 3rd Gen, it's a slam dunk great value for the money. Hundreds of guys are even running and racing them in the big B-bodies and going hundreds of thousands miles on them. I have a Street Edge 2800 in the Firebird behind the Vortec/ZZ4 engine and it blows away the S10 previously in there.
BTW, all of the Street Edge and Mild Street Edge converters for 700R4/4L60/E are lockup converters.
A lot of 4th Gen guys are running CircleD converters and all good reports. I haven't checked into them; they're a billet-type converter like Yank/Vig/Coan but priced slightly less.

I race my stuff, but my comments here are addressing street performance and streetability, stock-like heat generation, etc. Other than in the Impala, it's street first race second.

gbettner

iTrader: (2)

I'll just keep it simple and go with what 86 LG4bird suggested in the beginning. I was up until after 1AM this morning getting the engine swapped for extra money to buy this converter so I'll count my splines while I'm home for lunch and get it called in this afternoon. I'll call edge and ask for "Andre" I think you said and tell him I want a tight 9.5" lockup converter with at least a 2600 stall.

gbettner

iTrader: (2)

Street edge converter ordered!

gbettner

iTrader: (2)

Just realized yesterday that I couldn't find my cat back exaust out by the shed. I guess after paying for it at pic-a-part I left it there and forgot to load. I called them (2 weeks later) and they said they kept it for 2 days and then threw it in the dumpster.

gbettner

iTrader: (2)

Got cylinders 1-4 done. Takes forever to file fit rings,plastigauge rods, dis-assemble, clean off gauge wax, lube, and reassemble but I'm not in any rush so no need hurry it along. Getting exactly .002" oil clearance on all 4 rods so far, exactly .006" rod side clearance. All rings were within tolerance except for 3 of the 4 "second" compression rings. Oddly enough I was looking for minimum .018" gap and had .015-.016, all the siderails and top compression rings were within spec right out of the box.
Gave me a reason to use my new ring filing tool...... it's SWEET.

skinny z

Anything special (like a stretch gauge) for the final rod assembly? For years and years we assembled with only a torque wrench but it seems there's an improved method these days. I've had my last two short blocks assembled by the machine shop.

http://arp-bolts.com/p/technical.php

gbettner

iTrader: (2)

Well I finished up the rest of the clyinders tonight and checked piston "down in the hole" reading......... I think I'm screwed. Used a dial indicator, sraight edge, and feeler gauges. Cylinder readings in the hole are as follows....

1=.038
2=.037
3=.038
4=.038
5=.036
6=.036
7=.041
8=.036

My piston pin height was supposedly stock 1.560 according to part #, not sure where things went wrong. To play it safe I asked the machinist how much he took off the rods when reconditioning them. He told me only .003 which I believe would divide into only effecting deck heigt by .0015 which wouldn't hurt anything.

With my .015 head gasket it looks like I can only obtain .051-.057 quench. What are my options? tear the block back down and have it decked .010 like I should have to begin with? Or can I accomplish easier by milling the heads? I've already had heads resurfaced but not sure if that takes much meat off or not.

Am I worrying about nothing?

PLEASE HELP!

gbettner

iTrader: (2)

Thanks for the heads up. Instead of assuming it would be close enough I checked like you said. All info in above post.

1gary

One of the reasons 0 deck is so popular is it is a easy value of quench to hit when using D cup pistons which gives you the quench value on the flat part of the piston in conjunction with a .040 head gasket that doesn't require any special surface like some of the shim gaskets do or should be done and the compression relief in the d cup of the piston.

If it where me,I would run a mechanist straight edge corner to corner on the deck and measure how far off you are.Trying to save a deck,which time very well be now to deck it,and use a shim gasket too it really bad idea.Really you should have a flat deck ref'ed to the crank center line for a base to work off of. It's kind of like unequal head chambers and then compounding that with unequal piston to deck heights.That get complicated in a hurry and never a winning combo.

skinny z

I guess what you have to ask to what extent is the preferred .040" absolutely necessary.
The short answer is rarely.
Tens of thousands of SBC builds are racing around with quench as much as yours or more. What they're giving up in terms of performance or efficiency would be hard to measure.
Remember that I'm not talking about A Pro Mod engine here, or any other all out effort. It seems to me you're trying to put together a decent street engine and as such I can't see the point, labour-wise or dollar-wise in getting the block decked.
Case in point, (and Gary and I have had this discussion..sort of), my own Gen 1 SBC had a piston below deck value of .036" (range from .025- .036). I used a .026" gasket and the result was a .062" head/piston clearance. That was side by side with a cylinder that had a .025" piston depth and quench of .051". After a tear down and looking at all the obvious, there didn't appear to be any apparent differences between the two. Piston top colour and combustion patterns looked the same as did the plugs.
What does all that mean? Since you're asking my opinion, I'd say forge ahead without getting the block decked however....you now have to consider the SCR.
I haven't read back to see if you've selected a cam and that spec will determine (in part) the static compression ratio target. What I'm unsure about is the shim gasket. There are too many reports of the shim gaskets being unreliable on less than perfect block decks. If you were to deck the block then the shim may fit the bill however, without a decking, then I'd be reluctant to try. That said, you look at your options. My personal favourite is the Victor Reinz/Clevite 5746 .026" graphite gasket.
A quick run through the calculator says with: 64 cc head, piston depth .041", valve reliefs 6 cc, 4.03 x 3.48 bore/stroke and a .026" gasket yields a SCR of 9.75:1. That's a fine number for a mid-sized cam. Even if your quench is at .066" on one or two cylinders, you'll likely not need the added insurance against detonation that the tighter quench offers.
This is all very close to home as I'm in the middle of assembling my own engine and have to make that same choice regarding head gaskets. I'm stuck with a .014" piston depth and my choice of gasket, the .026", makes for that .040" clearance but puts the SCR up to 10.4:1, which when combined with the short cam timing, makes the engine unworkable. So much so that I've pulled the heads, taken a couple of cc out of the chambers and will reassemble with a thicker head gasket. Goodbye nice tight quench.

skinny z

I can understand the logic but I still don't agree.
If you're decking the block, then the amount doesn't matter as far as the machining process goes. .010" or .040". The mill doesn't care. Just select a target that when combined with the head gasket yields your targeted quench value. There's actually a benefit to the slightly thinner head gasket (without getting into shim territory) and that's the reduced amount of end gas that's trapped in the gap between the head and the block. You can cut that amount by almost half with an .026" compared to a .040". Now I know I'm splitting hairs here however if we're going to discuss the advantages of matching of the piston depths then were going beyond a straight forward street build.
Just to carry this a little further, if the objective were to equalize all of the piston depths, then it's entirely likely that the stack up between the assembled heights of the piston/rod combination and the throws of the crank will have to be addressed. I haven't checked on the cost of getting a crank indexed but I can bet it's not in the typical budget.
Like I said in a previous post, this isn't a Pro Mod engine. It's a sensibly hopped up street performance engine and the very nature of the beast leaves room for improvements on many levels. You just have to draw a line somewhere.

gbettner

iTrader: (2)

Thanks guys, Lot's to think about. Talked to the machine shop and they said if I decided to have deck work done it's 130.00 bucks. They said I could bring the assembled shortblock in for them to measure, then bring it back home, disassemble, and return for them to deck. Otherwise they would have to charge me 400 more dollars for disassembly/reassembly. So I'm considering at least having them measure it to make sure I did it right and go from there. Pretty frustrating but for a day or 2 worth of labor and trouble and 130bucks I'm considering it.

Thanks for the great advice skinny and Gary ( that's my name too). If they can set me up with a close as possible .014 down in the hole give or take a smidge and true it up a little and allowing me to throw a little thicker gasket on I may go for it. Haven't made my mind up. Might still just go with the bigger quench and roll with it.

Decisions decisions..................

skinny z

Describing it like you have I'd be inclined to going for it myself. Seeing as your engine is on a stand and you haven't gotten into the final assembly (or have you?), then you haven't lost much in terms of labour.
I'd like to see your machine shops answer to the difference in piston depth. You can bet that it's not the deck that's out that much and bringing all of those numbers in line would involve more than decking.
You may want to work out your target static compression ratio relative to what the cam needs before you decide to move ahead with the decking. That SCR value may influence the amount you get decked one way or the other.

gbettner

iTrader: (2)

My cam specs are as follows...



Brand:
Lunati


Manufacturer's Part Number:
20080721


Part Type:
Camshafts


Product Line:
Lunati Voodoo Camshafts


Summit Racing Part Number:
LUN-20080721




UPC:
090127693551


Cam Style:
Hydraulic roller tappet


Basic Operating RPM Range:
1,800-5,800


Intake Duration at 050 inch Lift:
219


Exhaust Duration at 050 inch Lift:
227


Duration at 050 inch Lift:
219 int./227 exh.


Advertised Intake Duration:
270


Advertised Exhaust Duration:
278


Advertised Duration:
270 int./278 exh.


Intake Valve Lift with Factory Rocker Arm Ratio:
0.515 in.


Exhaust Valve Lift with Factory Rocker Arm Ratio:
0.530 in.


Valve Lift with Factory Rocker Arm Ratio:
0.515 int./0.530 exh.


Lobe Separation (degrees):
112


Computer-Controlled Compatible:
Yes


Grind Number:
VDSC-270


Valve Springs Required:
Yes


Quantity:
Sold individually.


In-Store Pickup:
Choose In-store pick-up (OH, GA, NV) on our web site.

Unless you're a witch doctor, choosing the correct cam can be nightmare. These Voodoo cams from Lunati are the answer! The gurus at Lunati have taken cam design to another dimension with profiles never before utilized in cams. Only the world's best profiles are included in this line, making cam selection an easy choice. Voodoo incorporates 30 years of cam design experience with more recent developments in profiles, geometry, and tolerances to deliver the most aggressive ramp profiles ever used in hydraulic flat tappet cams. Asymmetrical lobe designs with slower closing sides set the valve down easy to reduce noise and premature failure of the valvetrain. These cams deliver more "area under the curve," meaning more throttle response, quicker acceleration, more vacuum, and better efficiency, combined with maximum horsepower and torque.



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Doesn't say anything about optimal CR. I'll have to look into it.

Wander if we could be looking at just way too much ground off the rods when reconditioning? The guy laughed when I asked him how much he ground off when resizing saying only .003 which he told me is thinner than a sheet of paper. If I have a beautiful seemingly perfect reground crank with perfect plastigauge oil clearances, new pistons, and resized rods. Does it make sense the rods were ground too much? I don't want to jump to conclusions but hat the heck else could it be?

I wander if my piston height would be spot on to what I was expecting if I popped a virgin stock rod and piston in there? I have a nice complete 85 longblock I can ****** a piston/rod out of for curiosity sake. It wouldn't be completely accurate since it would be stock bore piston vs .030 over cylinder but might be rough enough to tell.

HHHMMMMMMMM.

3rdgenmaro

iTrader: (9)

With them all being within .005" of each other, what is the tolerances in the rods, pistons, and crank? Im no engine builder, but couldnt a slightly longer rod, within tolerance of course, cause this too?

skinny z

Production tolerances could easily stack up to what you've measured. I'd bet that there's more than 5 thousandths between your longest and shortest rods. The throws on the crank could also be off that much. It would take a lot to bring everything to the same value. A quality aftermarket reciprocating assembly would be held to a tighter spec and that would show up in your piston depth measurements. Whether you want to sweat the small tolerances is up to you. There are probably plenty of opinions too.

gbettner

iTrader: (2)

I just ordered a 24"straight edge. As soon as it comes I'll check my deck to determine my next move. That should tell me for sure what's off more.... deck or piston hieght.

skinny z

If you're not familiar with this paper you may find it an interesting read.
It'll help you zero in on a workable combination.

http://cochise.uia.net/pkelley2/DynamicCR.html

Without crunching any of the numbers I'd say that with a cam of that size, a compression ratio in the mid 9's might be at the high end of what's workable.
Is this a daily driven street vehicle? Stuck in traffic sometimes? You'll want to keep these things in mind when deciding on your final CR. A cam works within a range and under certain conditions keeping away from the limit will help the drivability. Racing engines are a different story.
Can you produce the cam card? It'll have a few more details than what you posted. Intake centre line angle (ICL) and Lobe Seperation Angle (LSA) are required to calculate your running or dynamic compression ratio. You've supplied the LSA.
Keep in mind that if you build towards a tight quench, your static compression ratio given the specs of your engine, will be much too high for that cam. Somewhere along the lines of 10.4:1 is the result of a 64 cc head and a flat top piston when the piston to head clearence is .040".